This invention relates to priming systems for an internal combustion engine. More particularly, this invention relates to such priming systems for engines running on a relatively heavy fuel, and using a relatively lighter fuel for priming.
Priming systems are known for gasoline powered internal combustion engines. These priming systems typically deliver a small amount of raw gasoline into the carburetor throat, to increase the startability of the engine during cold starting.
In many countries, the engines operate on a heavier fuel than gasoline, such as kerosene, JP8 or diesel fuel. These heavier fuels are less volatile, and consequently it is difficult to start an engine that operates on a heavier fuel, particularly when the engine is cold.
To overcome this problem, it is known to use a lighter fuel such as gasoline as a priming fuel, and then change over to the heavier fuel during engine operation. Such prior art priming systems typically include relatively expensive electrically operated solenoid valves or special carburetors having two float bowls, or a partitioned float bowl with two chambers, to accommodate the two fuels. Thus, these prior art priming systems are typically expensive to manufacture and assemble.
To increase the startability of such dual fuel engines, it is known to manually drain the carburetor fuel bowl of the heavier fuel before engine starting. Some prior art priming systems have a valve that is manually operated to drain the fuel into a container or, more commonly, to drain the fuel directly on the ground. The disadvantages of these prior art priming systems is that they require several steps to operate, the drained fuel is often wasted, and the drained fuel may be left to evaporate into the atmosphere.